(19)
(11) EP 1 355 403 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
23.08.2006 Bulletin 2006/34

(43) Date of publication A2:
22.10.2003 Bulletin 2003/43

(21) Application number: 03008478.4

(22) Date of filing: 11.04.2003
(51) International Patent Classification (IPC): 
H02J 9/06(2006.01)
 H02M 3/158(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR
Designated Extension States:
AL LT LV MK

(30) Priority: 16.04.2002 JP 2002113117

(71) Applicants:
  • Hitachi, Ltd.
    Chiyoda-ku, Tokyo 100-8010 (JP)
  • HITACHI MAXELL, LTD.
    Ibaraki-shi, Osaka 567-8567 (JP)
  • HITACHI COMPUTER PERIPHERALS CO., LTD.
    Ashigarakami-gun, Kanagawa-ken, 259-01 (JP)

(72) Inventors:
  • Nemoto, Minehiro, Hitachi, Ltd., Intel Prop Group
    Chiyoda-ku, Tokyo 100.8220 (JP)
  • Kanouda, Akihiko, Hitachi, Ltd., Intel Prop Group
    Chiyoda-ku, Tokyo 100.8220 (JP)
  • Takahashi Fumikazu, Hitachi Ltd., Intel Prop Group
    Chiyoda-ku, Tokyo 100.8220 (JP)
  • Hamaogi, Masahiro
    Nakaimachi, Ashigarakami-gun, Kanagawa (JP)
  • Takahashi, Yoshihide
    Nakaimachi, Ashigarakami-gun, Kanagawa (JP)
  • Tanabe, Takashi
    Nakaimachi, Ashigarakami-gun, Kanagawa (JP)
  • Gotou, Takao
    Nakaimachi, Ashigarakami-gun, Kanagawa (JP)
  • Isogai, Masato
    Ibaraki-shi, Osaka (JP)
  • Miyata, Toshikatsu
    Ibaraki-shi, Osaka (JP)

(74) Representative: Strehl Schübel-Hopf & Partner 
Maximilianstrasse 54
80538 München
80538 München (DE)

   


(54) DC backup power supply device and method for diagnosing the same


(57) A reliable uninterruptible DC power supply device. The DC backup power supply device includes an AC/DC converter (2), a DC/DC converter (3), voltage step-up/down choppers (151, 152, 16, 18) and a battery (19) connected to a DC path of a main circuit connected with a load (4) via a switching means (13), and a microcomputer (20). In the device, under control of the microcomputer, the voltage step-up/down choppers are first operated under a condition that the MOS FET (13) was turned OFF for self diagnosis of the backup power supply device. Next, the switching means (13) is turned ON to execute the remaining self diagnosis. The DC backup power supply device can execute its self diagnosis with a lessened likelihood of danger of exerting an adverse effect on the main circuit and also can exhibit a reliable uninterruptible power supply function.







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